This study will look at changes in pig lung associated with copper deficiency and also changes associated with copper deficient animals that have been supplemented with zinc. A marked deficiency in elastic tissue has been noted in animals on the zinc supplementation. The compliance of these lungs are altered significantly. We will raise a number of pigs on the modification diets. We will evaluate their pulmonary function under anesthesia, and after exsanguination the lungs will be removed for pressure volume studies and for biochemical studies of elastic tissue as well as evaluation of morphology. Through this study we wish to better define the role of elastic tissues in the function of the normal lung.